Marketing Efficiency Ratio (MER): Ad Spend to Revenue

Marketing Efficiency Ratio (MER) measures what percentage of your order revenue is spent on advertising. Lower is better—it means more revenue per ad dollar.

Formula

MER = ( Total Ad Spend ÷ Total Order Revenue ) × 100

Formula Components

Metric	Definition
Total Ad Spend	Combined advertising spend across all connected platforms
Total Revenue	Total order revenue including shipping and taxes

Metadata
Type	Percentage
Data Source	Shopify, Meta Ads, Google Ads
Aggregation	Ratio

Example

Your Shopify store generated $200,000 in total revenue while spending $40,000 on advertising.

Metric	Value	Calculation
Total Ad Spend	$40,000	All ad platforms
Total Order Revenue	$200,000	All Shopify orders
MER	20%	($40,000 ÷ $200,000) × 100

A MER of 20% means you spend $0.20 on advertising for every $1 of revenue generated.

How It Works

MER is the inverse of ROAS expressed as a percentage. While ROAS tells you how much revenue per ad dollar, MER tells you what portion of revenue goes to advertising. MER is often preferred for budget planning because it directly shows ad spend as a percentage of revenue.

When to Use

Scenario	Action
Budget planning	Set target MER as percentage of projected revenue
Cross-channel comparison	Compare MER across platforms
Profitability analysis	Ensure MER leaves room for margins
Trend monitoring	Track MER over time to spot efficiency changes

Metric	Relationship
MER (Gross Sales)	MER using gross revenue before discounts/refunds
MER (Net Sales)	MER using net revenue after discounts/refunds
ROAS	The inverse metric (revenue per ad dollar)
Total Revenue	The denominator in this calculation

See all Performance metrics →

⌘I

​Formula

​Formula Components

​Example

​How It Works

​When to Use

​Related Metrics

Formula

Formula Components

Example

How It Works

When to Use

Related Metrics